'Dexter'

Au revoir, unholy Trinity (Season 4, Episode 12)Facile argument: Dexter was ruined the moment its second season revealed itself, early on, as a weak re-brew of everything those first 12 episodes had so beautifully concocted. (Kill, cover-up, stalk worse killer, rinse, repeat.) But the true shark-leap was the moment that distinguished gentleman actor John Lithgow was knocked off at the end of Season Four. Many memorable stars came and went in Showtime's serial-murderer drama, but in his single-season run as the Trinity Killer, Lithgow repeatedly stole the show — and then was forced to vacate it (at the same time as some crucial co-stars), leaving a huge void in his wake. You knew it was coming, yet the series never really recovered from the loss, and only worsened in its damnably formulaic approach as it bled out over four more long seasons. ZD